drivers/regulator/gpio-regulator.c

   1 /*
   2  * gpio-regulator.c
   3  *
   4  * Copyright 2011 Heiko Stuebner <heiko@sntech.de>
   5  *
   6  * based on fixed.c
   7  *
   8  * Copyright 2008 Wolfson Microelectronics PLC.
   9  *
  10  * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
  11  *
  12  * Copyright (c) 2009 Nokia Corporation
  13  * Roger Quadros <ext-roger.quadros@nokia.com>
  14  *
  15  * This program is free software; you can redistribute it and/or
  16  * modify it under the terms of the GNU General Public License as
  17  * published by the Free Software Foundation; either version 2 of the
  18  * License, or (at your option) any later version.
  19  *
  20  * This is useful for systems with mixed controllable and
  21  * non-controllable regulators, as well as for allowing testing on
  22  * systems with no controllable regulators.
  23  */
  24
  25 #include <linux/err.h>
  26 #include <linux/mutex.h>
  27 #include <linux/module.h>
  28 #include <linux/platform_device.h>
  29 #include <linux/regulator/driver.h>
  30 #include <linux/regulator/machine.h>
  31 #include <linux/regulator/gpio-regulator.h>
  32 #include <linux/gpio.h>
  33 #include <linux/slab.h>
  34
  35 struct gpio_regulator_data {
  36         struct regulator_desc desc;
  37         struct regulator_dev *dev;
  38
  39         int enable_gpio;
  40         bool enable_high;
  41         bool is_enabled;
  42         unsigned startup_delay;
  43
  44         struct gpio *gpios;
  45         int nr_gpios;
  46
  47         struct gpio_regulator_state *states;
  48         int nr_states;
  49
  50         int state;
  51 };
  52
  53 static int gpio_regulator_is_enabled(struct regulator_dev *dev)
  54 {
  55         struct gpio_regulator_data *data = rdev_get_drvdata(dev);
  56
  57         return data->is_enabled;
  58 }
  59
  60 static int gpio_regulator_enable(struct regulator_dev *dev)
  61 {
  62         struct gpio_regulator_data *data = rdev_get_drvdata(dev);
  63
  64         if (gpio_is_valid(data->enable_gpio)) {
  65                 gpio_set_value_cansleep(data->enable_gpio, data->enable_high);
  66                 data->is_enabled = true;
  67         }
  68
  69         return 0;
  70 }
  71
  72 static int gpio_regulator_disable(struct regulator_dev *dev)
  73 {
  74         struct gpio_regulator_data *data = rdev_get_drvdata(dev);
  75
  76         if (gpio_is_valid(data->enable_gpio)) {
  77                 gpio_set_value_cansleep(data->enable_gpio, !data->enable_high);
  78                 data->is_enabled = false;
  79         }
  80
  81         return 0;
  82 }
  83
  84 static int gpio_regulator_enable_time(struct regulator_dev *dev)
  85 {
  86         struct gpio_regulator_data *data = rdev_get_drvdata(dev);
  87
  88         return data->startup_delay;
  89 }
  90
  91 static int gpio_regulator_get_value(struct regulator_dev *dev)
  92 {
  93         struct gpio_regulator_data *data = rdev_get_drvdata(dev);
  94         int ptr;
  95
  96         for (ptr = 0; ptr < data->nr_states; ptr++)
  97                 if (data->states[ptr].gpios == data->state)
  98                         return data->states[ptr].value;
  99
 100         return -EINVAL;
 101 }
 102
 103 static int gpio_regulator_set_value(struct regulator_dev *dev,
 104                                         int min, int max)
 105 {
 106         struct gpio_regulator_data *data = rdev_get_drvdata(dev);
 107         int ptr, target, state, best_val = INT_MAX;
 108
 109         for (ptr = 0; ptr < data->nr_states; ptr++)
 110                 if (data->states[ptr].value < best_val &&
 111                     data->states[ptr].value >= min &&
 112                     data->states[ptr].value <= max)
 113                         target = data->states[ptr].gpios;
 114
 115         if (best_val == INT_MAX)
 116                 return -EINVAL;
 117
 118         for (ptr = 0; ptr < data->nr_gpios; ptr++) {
 119                 state = (target & (1 << ptr)) >> ptr;
 120                 gpio_set_value(data->gpios[ptr].gpio, state);
 121         }
 122         data->state = target;
 123
 124         return 0;
 125 }
 126
 127 static int gpio_regulator_set_voltage(struct regulator_dev *dev,
 128                                         int min_uV, int max_uV,
 129                                         unsigned *selector)
 130 {
 131         return gpio_regulator_set_value(dev, min_uV, max_uV);
 132 }
 133
 134 static int gpio_regulator_list_voltage(struct regulator_dev *dev,
 135                                       unsigned selector)
 136 {
 137         struct gpio_regulator_data *data = rdev_get_drvdata(dev);
 138
 139         if (selector >= data->nr_states)
 140                 return -EINVAL;
 141
 142         return data->states[selector].value;
 143 }
 144
 145 static int gpio_regulator_set_current_limit(struct regulator_dev *dev,
 146                                         int min_uA, int max_uA)
 147 {
 148         return gpio_regulator_set_value(dev, min_uA, max_uA);
 149 }
 150
 151 static struct regulator_ops gpio_regulator_voltage_ops = {
 152         .is_enabled = gpio_regulator_is_enabled,
 153         .enable = gpio_regulator_enable,
 154         .disable = gpio_regulator_disable,
 155         .enable_time = gpio_regulator_enable_time,
 156         .get_voltage = gpio_regulator_get_value,
 157         .set_voltage = gpio_regulator_set_voltage,
 158         .list_voltage = gpio_regulator_list_voltage,
 159 };
 160
 161 static struct regulator_ops gpio_regulator_current_ops = {
 162         .is_enabled = gpio_regulator_is_enabled,
 163         .enable = gpio_regulator_enable,
 164         .disable = gpio_regulator_disable,
 165         .enable_time = gpio_regulator_enable_time,
 166         .get_current_limit = gpio_regulator_get_value,
 167         .set_current_limit = gpio_regulator_set_current_limit,
 168 };
 169
 170 static int __devinit gpio_regulator_probe(struct platform_device *pdev)
 171 {
 172         struct gpio_regulator_config *config = pdev->dev.platform_data;
 173         struct gpio_regulator_data *drvdata;
 174         struct regulator_config cfg = { };
 175         int ptr, ret, state;
 176
 177         drvdata = devm_kzalloc(&pdev->dev, sizeof(struct gpio_regulator_data),
 178                                GFP_KERNEL);
 179         if (drvdata == NULL) {
 180                 dev_err(&pdev->dev, "Failed to allocate device data\n");
 181                 return -ENOMEM;
 182         }
 183
 184         drvdata->desc.name = kstrdup(config->supply_name, GFP_KERNEL);
 185         if (drvdata->desc.name == NULL) {
 186                 dev_err(&pdev->dev, "Failed to allocate supply name\n");
 187                 ret = -ENOMEM;
 188                 goto err;
 189         }
 190
 191         drvdata->gpios = kmemdup(config->gpios,
 192                                  config->nr_gpios * sizeof(struct gpio),
 193                                  GFP_KERNEL);
 194         if (drvdata->gpios == NULL) {
 195                 dev_err(&pdev->dev, "Failed to allocate gpio data\n");
 196                 ret = -ENOMEM;
 197                 goto err_name;
 198         }
 199
 200         drvdata->states = kmemdup(config->states,
 201                                   config->nr_states *
 202                                          sizeof(struct gpio_regulator_state),
 203                                   GFP_KERNEL);
 204         if (drvdata->states == NULL) {
 205                 dev_err(&pdev->dev, "Failed to allocate state data\n");
 206                 ret = -ENOMEM;
 207                 goto err_memgpio;
 208         }
 209         drvdata->nr_states = config->nr_states;
 210
 211         drvdata->desc.owner = THIS_MODULE;
 212
 213         /* handle regulator type*/
 214         switch (config->type) {
 215         case REGULATOR_VOLTAGE:
 216                 drvdata->desc.type = REGULATOR_VOLTAGE;
 217                 drvdata->desc.ops = &gpio_regulator_voltage_ops;
 218                 drvdata->desc.n_voltages = config->nr_states;
 219                 break;
 220         case REGULATOR_CURRENT:
 221                 drvdata->desc.type = REGULATOR_CURRENT;
 222                 drvdata->desc.ops = &gpio_regulator_current_ops;
 223                 break;
 224         default:
 225                 dev_err(&pdev->dev, "No regulator type set\n");
 226                 ret = -EINVAL;
 227                 goto err_memgpio;
 228                 break;
 229         }
 230
 231         drvdata->enable_gpio = config->enable_gpio;
 232         drvdata->startup_delay = config->startup_delay;
 233
 234         if (gpio_is_valid(config->enable_gpio)) {
 235                 drvdata->enable_high = config->enable_high;
 236
 237                 ret = gpio_request(config->enable_gpio, config->supply_name);
 238                 if (ret) {
 239                         dev_err(&pdev->dev,
 240                            "Could not obtain regulator enable GPIO %d: %d\n",
 241                                                 config->enable_gpio, ret);
 242                         goto err_memstate;
 243                 }
 244
 245                 /* set output direction without changing state
 246                  * to prevent glitch
 247                  */
 248                 if (config->enabled_at_boot) {
 249                         drvdata->is_enabled = true;
 250                         ret = gpio_direction_output(config->enable_gpio,
 251                                                     config->enable_high);
 252                 } else {
 253                         drvdata->is_enabled = false;
 254                         ret = gpio_direction_output(config->enable_gpio,
 255                                                     !config->enable_high);
 256                 }
 257
 258                 if (ret) {
 259                         dev_err(&pdev->dev,
 260                            "Could not configure regulator enable GPIO %d direction: %d\n",
 261                                                 config->enable_gpio, ret);
 262                         goto err_enablegpio;
 263                 }
 264         } else {
 265                 /* Regulator without GPIO control is considered
 266                  * always enabled
 267                  */
 268                 drvdata->is_enabled = true;
 269         }
 270
 271         drvdata->nr_gpios = config->nr_gpios;
 272         ret = gpio_request_array(drvdata->gpios, drvdata->nr_gpios);
 273         if (ret) {
 274                 dev_err(&pdev->dev,
 275                    "Could not obtain regulator setting GPIOs: %d\n", ret);
 276                 goto err_enablegpio;
 277         }
 278
 279         /* build initial state from gpio init data. */
 280         state = 0;
 281         for (ptr = 0; ptr < drvdata->nr_gpios; ptr++) {
 282                 if (config->gpios[ptr].flags & GPIOF_OUT_INIT_HIGH)
 283                         state |= (1 << ptr);
 284         }
 285         drvdata->state = state;
 286
 287         cfg.dev = &pdev->dev;
 288         cfg.init_data = config->init_data;
 289         cfg.driver_data = &drvdata;
 290
 291         drvdata->dev = regulator_register(&drvdata->desc, &cfg);
 292         if (IS_ERR(drvdata->dev)) {
 293                 ret = PTR_ERR(drvdata->dev);
 294                 dev_err(&pdev->dev, "Failed to register regulator: %d\n", ret);
 295                 goto err_stategpio;
 296         }
 297
 298         platform_set_drvdata(pdev, drvdata);
 299
 300         return 0;
 301
 302 err_stategpio:
 303         gpio_free_array(drvdata->gpios, drvdata->nr_gpios);
 304 err_enablegpio:
 305         if (gpio_is_valid(config->enable_gpio))
 306                 gpio_free(config->enable_gpio);
 307 err_memstate:
 308         kfree(drvdata->states);
 309 err_memgpio:
 310         kfree(drvdata->gpios);
 311 err_name:
 312         kfree(drvdata->desc.name);
 313 err:
 314         return ret;
 315 }
 316
 317 static int __devexit gpio_regulator_remove(struct platform_device *pdev)
 318 {
 319         struct gpio_regulator_data *drvdata = platform_get_drvdata(pdev);
 320
 321         regulator_unregister(drvdata->dev);
 322
 323         gpio_free_array(drvdata->gpios, drvdata->nr_gpios);
 324
 325         kfree(drvdata->states);
 326         kfree(drvdata->gpios);
 327
 328         if (gpio_is_valid(drvdata->enable_gpio))
 329                 gpio_free(drvdata->enable_gpio);
 330
 331         kfree(drvdata->desc.name);
 332
 333         return 0;
 334 }
 335
 336 static struct platform_driver gpio_regulator_driver = {
 337         .probe          = gpio_regulator_probe,
 338         .remove         = __devexit_p(gpio_regulator_remove),
 339         .driver         = {
 340                 .name           = "gpio-regulator",
 341                 .owner          = THIS_MODULE,
 342         },
 343 };
 344
 345 static int __init gpio_regulator_init(void)
 346 {
 347         return platform_driver_register(&gpio_regulator_driver);
 348 }
 349 subsys_initcall(gpio_regulator_init);
 350
 351 static void __exit gpio_regulator_exit(void)
 352 {
 353         platform_driver_unregister(&gpio_regulator_driver);
 354 }
 355 module_exit(gpio_regulator_exit);
 356
 357 MODULE_AUTHOR("Heiko Stuebner <heiko@sntech.de>");
 358 MODULE_DESCRIPTION("gpio voltage regulator");
 359 MODULE_LICENSE("GPL");
 360 MODULE_ALIAS("platform:gpio-regulator");